Signaling system



- W. C. WHITE.

SIGNALING SYSTEM. APPLICATION FILED JULY 3. 1920.

Patented Oct. 18, 1921.

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uurrsl) STATES PATENT orrica- WILLIAM 0. WHITE, OE SCHENECTAJJY, NEWYORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

SIGNALING SYSTEM.

Specification of Letters Patent.

Patented Oct. 18, 1921.

Application filed July 3, 1920.- Serial No. 393,812.

To all whom it may concern:

Be .it known that 1, WILLIAM vC. WHITE, a citizen of the United States,residing at Schenectady, county of Schenectady, State of New York, haveinvented certain new and useful Improvements in Signaling Systems, ofwhich the following is a specification.

My present invention relates to signaling systems, and more particularlyto systems for transmitting signals by means of high frequency currents.

The object of my invention is to provide a simple and eflicient systemfor transmittin high frequency signaling currents in which the energyfor the operation of the system is derived from a source of alternatingcurrent of the usual commercial low frequency.

In my Patent 1,195,632, August 22, 1916, I'have described a transmittingsystem for radio signaling in which the energy for the operation of thesystem is derived from an alternating current source of low frequency.In this case, rectifiers are provided for rectifying the low frequencycurrent and thus furnishing a direct current for the operation ofelectron discharge high frequency oscillators and modulators.

I have now discovered that by suitable circuit arrangements therectifiers in such a system may be entirely J dispensed with and therectifying properties of the oscillating and modulating devicesthemselves may be utilized for producing the desired rectification ofthe low frequency current.

Thenovel features which I believe to be' for supplying energy for theoperation of.

the electron discharge oscillators 2 and 3, and the modulators 4 and 5,these oscillators and modulators being preferably of the usualthree-electrode high vacuum type. Current for heating the'filamentarycathodes of the oscillators and modulators is also derived from thesource 1, being supplied to the cathodes by means of the transformer 6,the middle point 7 of which is preferably grounded. Current for theoperation of the oscillators and modulators is supplied to the platecircuits by means of the transformer 8, the secondary of transformer 8being oppositely connected to theplate circuits of the oscillators 2 and3 as well as to the plate circuits of the modulators 1 and 5. The platecircuits of the oscillators and modulators are all completed by aconnection from the middle point 9 of the secondary of the transformer 8through a reactance 10 to ground at 11. The circuit by which energy issupplied for the operation of the oscillator 2 may be traced out asfollows:

rom ground 11 through high inductance 10, through one-half of thesecondary of the transformer 8, radio choke coil 11, anode 12, cathode13, back to earth at 7. The circuit by which energy is supplied for theoperation of the oscillator 3 mcludes the other half of the secondary oftransformer 8 and a radio frequency choke coil 14. The circuit by whichenergy is supplied for the operation of the modulator 4 starting fromground 11 includes the high inductance 10, one-half of the secondary ofthe transformer 8, plate 15, cathode 16, back to earth at 7. The platecircuit of the modulator 5 is supplied With energy from the other halfof the transformer 8. In shunt to the cathode and anode of oscillators 2and 3, circuits are connected through which the high frequency currentscirculate made up of condensers 17 and 18 for preventing low frequencycurrents from flowing in the circuits and the inductance 19, which iscommon to both circuits. The grid circuits of the oscillators 2 and 3both include the inductance 20 cou- 1 pled to the inductance 19 and theusual grid the high frequency current in the antenna is effected byimpressing the modulating current upon the grid circuits of themodulators 4 and 5. In the present case I have indicated as a means forimpressing the signaling current upon the grid circuits of thesemodulators the local circuit of the oscillators and the modulators.

potential suitable for the best operation of the modulators.

It will be observed that the inductance 10 is common to the platecircuits of boththe When a slgnaling current is impressed upon the gridcircuits of the modulators the potential drop across the inductance 10varies in accordance with the variations in the signaling current andthe potential supplied to the oscillating circuits of the oscillators 2and 3 varies accordingly thereby producing a corresponding modulation ofthe high frequency current produced in the antenna. .The

inductance 10 also acts to smooth out the low frequency variations inthe current sup:

' plied to thejoscillators and modulators. By

' high *frequency'currents generated and of .ulator tubes 4 and 5. A ofthe coupling coils 19 and 20 is connected proper" design ofthisinductance I have i found that the variations in this current supply maybesmoothed out to such an extent as. to introduce no objectionable lowfrequency variations in I the modulated high frequency current. r

The radio frequencychoke coils 11" and 14 serve the double purpose ofprotecting the secondary of the transformer 8 from the preventing thesehigh frequency currents from being short circuited through the mod- Oneterminal of each toearth at 11-. and as a result although the lowfrequency potential applied to the system from the secondary of thetransformer- 8 may be very high, the low frequency po--- tentials set upin the coils 19 comparatively low.

While I have indicated only one circuit arrangement whereby my inventionma be carried into -effect, it will be obvious to t ose and 20 will beskilled in the art that many-variations in the circuit. connections usedand in: the form of the apparatus employed may be made without departingfromthe scope of my invention as set forth in the appended claims.-

6 5 -2. The combination '1 a high frequency What I claim as new anddesire to secure by- Letter's Patent'of the United States, is,

1. The combination in "a high frequency signaling system of a pair ofelectron discharge devices having coupled plateand.

grid circuits, a source of low frequency alternating current oppositelyconnected to,

the plate circuits of thetwo devices, asecond pair of electron dischargedevices .hav-

ing plate and grid circuits, said source of low frequency current beingalso oppositely connected to the plate circuits of the second pair ofdevices, and an inductance which is common to the'plate-ci-rcuits of'allof the devices. i

' common to the cuits, said source of low frequencycurrent being alsooppositely connected to the plate circuits of the second pair ofdevices, and an inductance which is common to the plate circuits of allof the devices.

3. The combination in a high frequency signalingsystem of a pair ofelectron discharge devices having coupled plate and grid circuits, asource of low frequency alternating current oppositely connected to theplate circuits of the two devices, a second pair of electron dischargedevices having plate and grid circuits, said source of low frequencycurrent being also oppositely connected to the plate circuits of thesecond pair of devices, means for impressing signaling currents upon thegrid circuits of the second pair of devices, and an inductance which isI plate circuits of'all of the de- V1088.

4. The combination in a high frequency transmitting system,'ofanantenna, a pair of electron discharge devices having coupled plate and"grid circuits for producing radio frequency oscillations in saidantenna, a source of low frequency alternating current oppositelyconnected to theplate circuits of the two devices, a second pair ofelectron discharge devices having plate and 'grid circuits, said sourceof low frequency-current vbeing also oppositely connected to the platecircuits of the second pair of devices, means for impressing signalingcurrentsnupoifthe grid circuit of the second pair of devices, and aninductance which is common to the plate circuits of all of the devices.

5. The combination in a high frequency slgnaling system of a. pair ofelectron discharge. devices having coupled plate and grid circuits, asource. of low frequency alternatlng current oppositely connected to theplate circuits of the two devices, radio frequency choke coils in the.plate, circuits of said devices, a second pair of electron dlschar'gedevices having plate and grid circuits, said source of low frequencycurrent being also oppositely connected to the plate circuits of thesecond pair of devices, and

" an inductance Which is common to the plate circuits of all of thedevices. I

6.'.The combination in a high frequency transmitting system, of anantenna, a pair of electron discharge devices having coupled plate andgrid circuits for producing radio frequency oscillations in saidantenna, a source of low frequency alternating current oppositelyconnected to the plate circuits of Ill the two devices, radio frequencychokecoils in the plate circuits of said devices, a econd pair ofelectron discharge devices having plate and grid circuits, said sourceof low frequency current being also oppositely connected to the platecircuits of the second pair of devices, means for impressing signalingcurrents upon the grid circuits of the sec-' I coupling inductancesbeing rounded, a

source of low frequency alternating current oppositely connected to theplate circuits of the two devices, a second pair of electron dischargedevices having plate and grid circuits, said source of low frequencycurrent being also oppositely connected to the plate circuit of thesecond pair of devices, and an inductance which is common to the platecircuits of all of the devices.

8. The combination in a high frequency transmitting systemof an antenna,a pair of electron discharge devices having" inductively coupled plateand grid circuits for producing radio frequency oscillations in saidantenna one terminal of each of the coupling inductances being grounded,a source of low frequency alternating current oppositely connected tothe plate circuits of the two devices, a second pair of electrondischarge devices having plate and grid circuits, said source of lowfrequency current being also oppositely connected to the plate circuitsof the second pair of devices, means for impressing signaling currentsupon the grid circuits of the second pair of devices, and an inductancewhich is common to the plate circuits of all of the devices.

9. The combination in a high frequency signaling system of a pair ofelectron discharge devices having coupled grid and plate circuits, asource of low frequency alternating current oppositely connected to theplate circuits of the two devices and means for varying in accordancewith a ignaling current the potentials applied from said source to theelectrodes of said devices.

10. The combination in a high frequency signalin system of an antenna, apair of electron discharge devices having coupled grid and platecircuits for producing radio frequency oscillations in said antenna, asource of low frequency alternating current oppositely connected to ththe two devices, and means for varying in accordance with a signalingcurrent the potentials applied from said source to the electrodes ofsaid devices. In witness whereof I have hereunto set my hand this firstday of July, 1920.

WILLIAM C. WHITE.

e plate circuits of

